176 
TENTH REPORT. 
CONDITIONS IN SPRING. 
At the opening of this season the ground is partially covered with ice and 
snow, and the trees of course are bare. About the middle of April the trees 
begin to leave out and by the first of May are nearly leaved. The low vege- 
tation which covers part of the strip has not started even at this date. In- 
sects abound in the upper branches of the willows and furnish food for myriads 
of migrating birds. By the first of June all the plants are in full growth and 
many are in bloom. 
CHARACTERISTIC BIRDS. 
Zenaidura macroura (Linn.). Mourning dove. The Mourning Dove 
arrives about the first of March. At this time it does not remain much in 
the willows, but wanders about the dry meadow land back of the bluffs, 
returning to the willows at night. Very little food suitable for Mourning 
Doves exists in this station early in the spring, which accounts for its scar- 
city here before the breeding season. Waste grain and weed seeds form 
the principal diet, although some insects are eaten. It begins nesting long 
before the trees have started to leave out, one set of two fresh eggs being 
found the 28th of April, 1902. From this time on until the first of June, fresh 
eggs can be found. The nests are placed on the horizontal limbs, in the 
crotches and in every suitable place to be found in the large willows. The}' 
are constructed of dead stems, twigs and sometimes a few dry leaves and 
roots. This material is usually picked up beneath the tree where the nest 
is being built. The food of the adults consists of seeds of ragweed, sun- 
flower, and various other weeds and grasses. At first the young are fed on 
this food after it has been partially digested by the parent, but before they 
leave the nest they can eat entire seeds. Waste corn and other grains which 
remain from the previous year in the fields back of the bluffs are greedily 
eaten. Only four stomachs have been examined, but their contents repre- 
sent the characteristic food as determined by field observations. During 
the nesting season the doves are abundant at this station, but when nesting 
is over the majority leave and seek the open stubble fields. 
Icterus galbula (Linn.). Baltimore Oriole. The first Baltimore Orioles 
arrive the last of April and begin nest-builcling by the last of May. The 
birds as a rule remain in the tops of the tall willows when there is an abun- 
dant insect life. It is here on the ends of the swaying branches that they con- 
struct their nests. They are composed of gray plant fiber, and fastened on 
the extreme ends of the topmost branches, often overhanging the river. 
The nests are thus far beyond the reach of any enemies without wings. The 
food is entirely insectiverous and procured mainly in the tops of the willows. 
OTHER COMMON BIRDS. 
During the migration the most abundant birds are the warblers. Of 
these the most common are Black and White, Nashville, Yellow, Black- 
throated Green, and Redstart. Their migration extends from the first to 
the middle of May. These warblers feed almost entirely in the tops of the 
willows. The insect food found there accounts for their preference for this 
region. The Wood Be wee is found commonly in the higher willows. 
The Belted Kingfisher uses the dead branches of the willows overhanging 
the river as vantage posts from which to observe the fish below. In the 
